The invention relates to the repair of insulating glass units to equalize pressure between the space between panes and the atmosphere.
Insulating glass units are formed generally of a pair of glass panes that are generally parallel to one another and that have a spacer running between them at their peripheries. Spacers, commonly of metal, are adhered by means of a sealant to the glass panes, the sealant desirably forming a gas-tight seal to thus prevent air or other gas from entering or leaving the space between the panes. Insulating glass units are shown, for example, in U.S. Pat. Nos. 5,377,473 and 5,439,716.
To improve the insulating capacity of such glass units, the between-pane space may be filled with argon or other gas that has a coefficient of thermal conductivity less than that of air. Commonly, the between-pane space is filled with argon to a pressure that is approximately atmospheric, although pressure adjustments may be made in connection with the elevation of the geographic locale where the insulating glass unit is to be installed. The periphery of an insulating glass unit is encased in a frame which may be of wood or other material, and the wooden frame in turn may have a weather-resistant plastic coating.
Over a period of time, argon may slowly leak from the between-pane space to the atmosphere. This occurs at a rate greater than the permeation of oxygen or nitrogen into the between-pane space, with the result that the pressure in the between-pane space is reduced below atmospheric pressure. The resulting pressure differential causes the panes to cup inwardly, and the panes can eventually touch near their centers, with consequent loss of insulating value. In some cases, the cupping of the panes is so great as to cause one or the other of the panes to shatter. When failure occurs, the window units necessarily have to be replaced, and this can be extremely expensive in that the failed window unit must be removed, replaced, and reinstalled on a unit-by-unit basis.
When transported to geographic locations of higher elevation and hence reduced atmospheric pressure, the panes of insulating glass units may bulge outwardly under the pressure differential across the panes, and this also causes distortion of the panes and may lead to ultimate glass breakage.
It would be desirable to provide a method and apparatus to enable insulating glass units that bulge or that have become cupped to be repaired without requiring them to be removed from the frames within which they are encased, and without requiring them to be removed from the buildings in which they are installed.
In connection with insulating glass window units that have bulged or cupped panes due to pressure differentials across the panes, we have found that it is possible to repair the units in situ in a rapid, convenient and low cost manner. Speaking broadly, the method comprises drilling a bore through the frame which encases an insulating glass unit to expose an outer surface of a wall of the spacer, then drilling a hole through the spacer to enable air or other gas to enter or exit from the between-pane space to equalize the pressure between that space and the atmosphere. As the between-pane space reaches atmospheric pressure, the panes substantially regain their original parallelism. We then fill the bore formed in the frame with a waterproof sealing material such as a silicone rubber sealant.
Before filling the bore in the frame with a sealant, we prefer to first seal the hole drilled through the spacer wall, desirably by means of a rivet bearing a sealant. Other methods of sealing the spacer wall involve use of a small screw that is screwed into the hole formed in the spacer wall, the screw preferably also bearing a sealant to seal the hole n the spacer wall. One may also use an expanding screw, of the type used to mount pictures through dry wall panels. One such screw carries an expandable collar at its tip which expands into sealing contact with the hole in the spacer as the screw is rotated. The collar, in another example, may have longitudinal slots in it forming arms that bow out in accordion fashion as the screw is rotated, the arms expanding behind the rim of the spacer hole. Sealant is used about and within the expandable collars and arms as needed to form a gas tight seal.
In this manner, the hole in the spacer is itself provided with a first seal, and the sealant that is provided in the bore in the frame provides a second, backup seal, all for the purpose of resisting permeation of gas out of or into the between-pane space.
In a preferred embodiment, a drill bit is used having a stop that prevents the drill bit from penetrating further than a predetermined distance into the framed window unit. The drill bit has a first length that forms a bore through the frame but not through the spacer, and a second length carried distally of the first length and having a reduced diameter for forming a hole through a wall of the spacer.
Also in a preferred embodiment, a riveting gun is employed, the gun employing xe2x80x9cpopxe2x80x9d rivets, that is, rivets that can be inserted into a hole, and that have a connecting stem that can be withdrawn to conform the head of the rivet to the hole, following which the stem breaks off and is removed. The rivets may be provided with a sealant such as butyl rubber, preferably in the form of an annular ring carried about the diameter of the rivet. The sealant forms a seal between the rivet itself and the walls of the hole formed in the spacer wall to form an airtight seal. Riveting guns may be provided with extra long rivet-bearing shafts to enable them to reach deeply into the bores formed in extra wide window stiles.
In another embodiment, the invention provides a kit for the repair of insulating glass units. The kit includes a drill bit for drilling through the frame and the spacer wall, and a drill guide configured to mount to the frame of an insulated glass unit and having a bore sized to closely receive the drill bit with the bore aligned with the spacer between the panes to ensure proper placement of the bore to be drilled through the frame.
The drill bit, in a preferred embodiment, includes a stop preventing it from extending within the window unit from the edge of the frame by more than a predetermined distance. The purpose of the stop is to prevent the drill bit from extending completely through the spacer into the between-pane space when a bore is drilled through the frame. The drill bit may also include a first drill bit portion having a length enabling the distal end of the first portion to extend to but not beyond the exterior surface of the spacer wall, and a second drill bit portion of smaller diameter than the first and extending distally of the first portion for drilling a hole in the spacer wall. The stop may be a drill bit-mounted block configured to engage the edge of the guide when the drill bit has advanced through the frame and spacer wall for the predetermined distance.
To seal the hole formed in the spacer, it is preferred to employ a rivet sized to be received within the hole in a spacer wall. Desirably, the rivet includes a ring of deformable sealant about its circumference that is sized to engage the wall of the spacer surrounding the hole formed in it. The sealant thus seals to the rivet and to the edges of the hole when the rivet is mounted in the spacer hole.
It may be desired to in some circumstances to re-fill the between-pane space with argon or other gas as part of the repair routine. This may be accomplished through the use of a small hollow lance connected at one end to a source of gas under pressure and placing the other end of the lance through the hole in the spacer to deliver gas to the between-pane space. As argon or other gas is delivered to the space, gas from within the space may escape outwardly from the hole. The concentration of gas within the space at any time may be measured by measuring the gas concentrations escaping from the hole. Once the between-pane space has been appropriately purged, the hole and the bore through the frame are appropriately plugged as described above.